Characterization of isolated probiotic bacteria from traditional Maraghehyogurt

BACKGROUND AND OBJECTIVESAccording to the definitions of the World Health Organization (WHO) and the Food andAgriculture Organization (FAO), probiotics as living microorganisms by maintaining orimproving the microbial balance, can confer health benefits on their host. Probiotic bacteriaregulate the gut microbiota by adhering to the intestinal epithelial tissues, enhancing nutrientuptake, synthesizing vitamins and short-chain fatty acids, and modulating the pH of the gut.MATERIALS AND METHODSAfter isolation and purification, probiotic properties of the M۲۰ isolate were evaluated bygram staining, oxidase, catalase, hemolysis, and acid and bile salt resistance tests. Also,microbial tests including nitrate reduction, SIM, sugar fermentation, antibiotic resistance andantimicrobial were conducted. For molecular identification of the isolate, DNA was extractedusing a kit, PCR amplification of ۱۶S rRNA gene performed, electrophoresed andphylogenetic tree of the isolate constructed by neighbor-joining method by BioEdit andMEGA version ۷ softwares.RESULTS AND DISCUSSIONAccording to the results, the M۲۰ isolate was known as a probiotic bacteria due to grampositivemorphology, negative results for catalase and oxidase tests, resistance to bile saltsand acidic pH, and absence of hemolysis. The microbial tests indicated that the isolate wasresistant to antibiotics and capable of sugar fermentation and nitrate reduction. Based on themolecular identification result, the isolate showed highest genetic similarity (۸۶%) toLactobacillus plantarum DMS ۱۰۶۶۷ (T) CP۰۳۲۷۴۴. The nucleotide sequence of the M۲۰isolate has been deposited in the NCBI database under accession number OQ۵۶۸۱۹۷.Moreover, the production of asparaginase and glutaminase by the M۲۰ isolate, which areknown therapeutic enzymes, was confirmed.CONCLUSIONThe lactic acid bacteria isolated from traditional Maragheh yogurt exhibited probioticproperties, could be considered as a favorable candidate to use in food and pharmaceuticalindustries.